 /*
  * $Header: /cvshome/build/org.osgi.util.measurement/src/org/osgi/util/measurement/State.java,v 1.8 2006/06/16 16:31:34 hargrave Exp $
  *
  * Copyright (c) OSGi Alliance (2002, 2006). All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.osgi.util.measurement;

 /**
  * Groups a state name, value and timestamp.
  *
  * <p>
  * The state itself is represented as an integer and the time is measured in
  * milliseconds since midnight, January 1, 1970 UTC.
  *
  * <p>
  * A <code>State</code> object is immutable so that it may be easily shared.
  *
  * @version $Revision: 1.8 $
  */
 public class State {
     final int value;
     final long time;
     final String name;

     /**
      * Create a new <code>State</code> object.
      *
      * @param value The value of the state.
      * @param name The name of the state.
      * @param time The time measured in milliseconds since midnight, January 1,
      * 1970 UTC.
      */
     public State(int value, String name, long time) {
         this.value = value;
         this.name = name;
         this.time = time;
     }

     /**
      * Create a new <code>State</code> object with a time of 0.
      *
      * @param value The value of the state.
      * @param name The name of the state.
      */
     public State(int value, String name) {
         this(value, name, 0);
     }

     /**
      * Returns the value of this <code>State</code>.
      *
      * @return The value of this <code>State</code> object.
      */
     public final int getValue() {
         return value;
     }

     /**
      * Returns the time with which this <code>State</code> was created.
      *
      * @return The time with which this <code>State</code> was created. The time
      * is measured in milliseconds since midnight, January 1, 1970 UTC.
      */
     public final long getTime() {
         return time;
     }

     /**
      * Returns the name of this <code>State</code>.
      *
      * @return The name of this <code>State</code> object.
      */
     public final String getName() {
         return name;
     }

     /**
      * Returns a <code>String</code> object representing this object.
      *
      * @return a <code>String</code> object representing this object.
      */
     public String toString() {
         StringBuffer sb = new StringBuffer ();
         sb.append(value);
         if (name != null) {
             sb.append(" \"");
             sb.append(name);
             sb.append("\"");
         }
         return (sb.toString());
     }

     /**
      * Returns a hash code value for this object.
      *
      * @return A hash code value for this object.
      */
     public int hashCode() {
         int hash = value;
         if (name != null) {
             hash ^= name.hashCode();
         }
         return hash;
     }

     /**
      * Return whether the specified object is equal to this object. Two
      * <code>State</code> objects are equal if they have same value and name.
      *
      * @param obj The object to compare with this object.
      * @return <code>true</code> if this object is equal to the specified object;
      * <code>false</code> otherwise.
      */
     public boolean equals(Object obj) {
         if (this == obj) {
             return true;
         }
         if (!(obj instanceof State)) {
             return false;
         }
         State that = (State) obj;
         if (value != that.value) {
             return false;
         }
         if (name == that.name) {
             return true;
         }
         if (name == null) {
             return false;
         }
         return name.equals(that.name);
     }
 }

